A. Field of the Invention
This invention generally relates to manipulators of manufactured parts, and more particularly, to a manipulator for an automated digital X-ray inspection system for evaluating aircraft engine gas turbine blades.
B. Discussion
The manufacture of high performance, fuel efficient aircraft turbine engines has lead to the development of turbine blades containing complex interior passages and openings to the blade surface for blade cooling. Performance and life of the blades is dependent upon the manufacture of these interior structures within specification. A high penalty exists for blade failure because of machinery damage, incompletion of mission, and hazard to personnel. For these reasons 100% inspection of turbine blades is important to the public and a highly automated digital X-ray inspection station system has long been desired.
The automated X-ray inspection system includes an X-ray machine and an X-ray image system. The X-ray machine includes devices for manipulating parts, generating X-rays, detecting X-rays, and controlling the flow of parts through the X-ray machine. The X-ray image system includes computer hardware and software for acquiring X-ray data, image generation, archiving, displaying, performing computations, and controlling the X-ray machine. The system is a production type automatic inspection module capable of detecting internal flaws in jet engine turbine blades.
The X-ray inspection system operates as follows for a group of parts, such as turbine blades. The operator enters into the computer console information required to select as inspection plan from the computer system. The first part is then removed from an input box and the part serial number entered in the computer console. The operator then manually inserts the part into a conveyor gripper positioned at a load station. After the part is positioned the operator depresses the start buttons on the conveyor when ready. This operation is repeated for all parts. The conveyor advances the parts between load, inspection, and unload stations.
The part and gripper are automatically advanced to a part inspection station. The part grippers have variable holding configuration for accommodating a variety of parts to be inspected that are made of a material of lower X-ray absorptivity compared to the part material. When the part grippers reach the inspection station, a manipulator has to removed the part grippers from the conveyor and positions the part and grippers between an X-ray source and an X-ray detector. The manipulator moves the part within a directed x-ray beam for generating digital fluoroscopy and computed tomography images. After inspecting the blade, the manipulator replaces the gripper and part on the conveyor. The conveyor then moves the gripper and part to the unload station.
Therefore, it is an object of the present invention to provide a manipulator which controls positioning a gripper at a part inspection station.
It is an object of this invention to provide a manipulator which has two axes of movement, one axis is a vertical translation perpendicular to a directed X-ray beam, and the second is a rotation about the vertical axis.
It is an object of this invention to provide a manipulator that centers and aligns the gripper's center of axis about the vertical axis of the manipulator.
It is another object of this invention to provide a manipulator that acquires the gripper and holds the gripper firmly while positioning the gripper in the directed X-ray beam.
It is another object of this invention to provide a manipulator that provides timing pulses for data acquistion to the computer hardware based upon the motion of the gripper and part.